//
//  UIImage+Transparent.m
//  Taste
//
//  Created by 徐昊 on 16/9/1.
//  Copyright © 2016年 徐昊. All rights reserved.
//

#import "UIImage+Transparent.h"

@implementation UIImage (Transparent)
+ (UIImage*)imageToTransparent:(UIImage*)image
{
    // 分配内存
    const int imageWidth = image.size.width;
    const int imageHeight = image.size.height;
    size_t bytesPerRow = imageWidth * 4;
    uint32_t* rgbImageBuf = (uint32_t*)malloc(bytesPerRow * imageHeight);
    
    // 创建context
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    CGContextRef context = CGBitmapContextCreate(rgbImageBuf, imageWidth, imageHeight, 8, bytesPerRow, colorSpace,kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast);
    CGContextDrawImage(context, CGRectMake(0, 0, imageWidth, imageHeight), image.CGImage);
    // 遍历像素
    int pixelNum = imageWidth * imageHeight;
    uint32_t* pCurPtr = rgbImageBuf;
    for (int i = 0; i < pixelNum; i++, pCurPtr++)
    {
        if ((*pCurPtr & 0xFFFFFF00) == 0xffffff00) {
            uint8_t* ptr = (uint8_t*)pCurPtr;
            ptr[0] = 0;
        }
    }
    // 将内存转成image
    CGDataProviderRef dataProvider =CGDataProviderCreateWithData(NULL, rgbImageBuf, bytesPerRow * imageHeight, ProviderReleaseData);
    
    CGImageRef imageRef = CGImageCreate(imageWidth, imageHeight,8, 32, bytesPerRow, colorSpace,
                                        kCGImageAlphaLast |kCGBitmapByteOrder32Little, dataProvider,
                                        NULL, true,kCGRenderingIntentDefault);
    CGDataProviderRelease(dataProvider);
    
    UIImage* resultUIImage = [UIImage imageWithCGImage:imageRef];
    
    // 释放
    CGImageRelease(imageRef);
    CGContextRelease(context);
    CGColorSpaceRelease(colorSpace);
    
    return resultUIImage;
}


/** 颜色变化 */
void ProviderReleaseData (void *info, const void *data, size_t size)
{
    free((void*)data);
}
@end
